<br><br><div class="gmail_quote">On Thu, May 6, 2010 at 7:06 AM, Andreas Raab <span dir="ltr"><<a href="mailto:andreas.raab@gmx.de">andreas.raab@gmx.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Hi -<br>
<br>
I've been trying to wet my feet with Metacello a little by writing a ConfigurationOfWebClient and in the process I've come across various things that I don't understand or don't know how to express. The configuration itself can be found here:<br>
<br>
<a href="http://www.squeaksource.com/MetacelloRepository" target="_blank">http://www.squeaksource.com/MetacelloRepository</a><br>
<br>
Here are the questions I'm having:<br>
<br>
1) #includes: vs. #requires:<br>
What is the difference between #includes: and #requires:? They sound entirely interchangeable, in particular after reading the tutorial which states:<br>
<br>
"When you use the #includes: directive, you are not only specifying that the listed packages should be loaded when the parent package is loaded, but that the #included: packages should be loaded _before_ any packages that require the parent package."<br>
<br>
I would expect that precise behavior for required packages, i.e., if Foo requires: Bar then Bar is loaded before Foo if some other package requires: Foo. What am I missing?<br>
<br>
2) Why is HelpSystem not loaded?<br>
In my configuration, baseline specifies that HelpSystem is required for WebClient-Help:<br>
<br>
"Documentation doesn't require Core/Tests, but HelpSystem"<br>
spec package: 'WebClient-Help' with:[spec requires: 'HelpSystem'].<br>
<br>
spec project: 'HelpSystem' with:[<br>
spec<br>
className: 'ConfigurationOfHelpSystem';<br>
repository: '<a href="http://www.squeaksource.com/MetacelloRepository" target="_blank">http://www.squeaksource.com/MetacelloRepository</a>'<br>
].<br>
<br>
However, when executed, Metacello goes through the motions but doesn't actually *load* any version of HelpSystem (I can see it 'fetch' the packages but not load them). It even calls the postLoadDoIt on it (which fails since nothing was loaded). What am I doing wrong?<br>
<br></blockquote><div><br>Hi Andreas, I am not sure, but did you try setting also the file:<br><br> "Documentation doesn't require Core/Tests, but HelpSystem"<br>
spec package: 'WebClient-Help' with:[spec requires:
'HelpSystem'].<br>
<br>
spec project: 'HelpSystem' with:[<br>
spec<br>
className: 'ConfigurationOfHelpSystem';<br>
repository: '<a href="http://www.squeaksource.com/MetacelloRepository" target="_blank">http://www.squeaksource.com/MetacelloRepository</a>';<br> file: 'ConfigurationOfHelpSystem';<br>
].<br><br><br>I saw in your final version you added a version: '1.1' and I saw you put a comment saying that's a Metacello bug. It's weird since version: shouldn't be necessary there.<br>
<br>You should put it in the version.<br><br>spec <br> package: 'WebClient-Core' with: 'WebClient-Core-ar.16';<br> package: 'WebClient-Tests' with: 'WebClient-Tests-ar.7';<br>
package: 'WebClient-Help' with: 'WebClient-Help-ar.5';<br> package: 'WebClient-HTTP' with: 'WebClient-HTTP-ar.1'.<br>spec<br> project: 'HelpSystem' with: '1.1'.<br>
<br> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
3) When exactly is HelpSystem loaded?<br>
<br>
What I'm wondering about in the above is that HelpSystem should only be loaded if WebClient-Help is being loaded. Is this implicitly part of specifying a 'project' instead of a 'package'? Or is there some other way of specifying that?<br>
<br>
I guess really the question here is what entities get loaded implicitly simply by declaring them (packages for sure, any others?) and what entities need to be 'required' in order to be loaded?<br>
<br></blockquote><div><br>If you don't define groups in your configuration, it will load by default all the declarations: packages and projects. <br><br>If you want to change that, you can add to your conf something like this:<br>
<br>spec<br> group: 'default' with: #('Core' );<br> group: 'Core' with: #( 'WebClient-Core' "...");<br> group: 'Tests' with: #( 'WebClient-Tests' "...");<br>
"....."<br> yourself.<br><br>With that, when you call "load" it will only load Core. Then, you can do this:<br><br>(ConfigurationOfWebClient project version: '1.0') load: 'Test'<br>
or<br>(ConfigurationOfWebClient project version: '1.0') load: 'WebClient-Core'<br>or<br>(ConfigurationOfWebClient project version: '1.0') load: {'WebClient-Core' 'WebClient-HTTP'}.<br>
<br>The parameter to load: can be a package name, a group or an an array of them.<br><br> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
4) How does one define dependencies that differ based on platform?<br>
<br>
In WebClient, the WebClient-HTTP package requires WebClient-Core and -only for: #pharo- also WebClient-Pharo. How does one express that there's an additional dependency for WebClient-HTTP that only exists for: #pharo? The config currently specifies:<br>
<br>
spec for: #common do:[<br>
" ... "<br>
spec package: 'WebClient-HTTP' with:[spec requires: 'WebClient-Core'].<br>
" ... "<br>
].<br>
<br>
spec for: #pharo do:[<br>
"Just the fact it exists; no requirements here"<br>
spec package: 'WebClient-Pharo'.<br>
].<br>
<br></blockquote><div><br><br>The only thing that comes to my mind now is to do:<br><br><br> spec for: #common do:[<br>
" ... "<br>
spec package: 'WebClient-HTTP' with:[spec requires:
'WebClient-Core'].<br>
" ... "<br>
].<br>
<br>
spec for: #pharo do:[<br>
spec package: 'WebClient-HTTP' with:[spec requires: {
'WebClient-Core' 'WebClient-Pharo'} ].<br>
<br>].<br>
<br><br><br> </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Which means that WebClient-Pharo will be loaded on Pharo by default but it's missing the fact that WebClient-Pharo is in fact a requirement for WebClient-HTTP (but only on that platform). How is that best expressed?<br>
<br>
5) Bootstrapping Metacello?<br>
<br>
I found that most of the ConfigurationsOfXXX include some code to 'bootstrap' Metacello in some form. There appear to be variants on the code; is there a "canonical bootstrap method" that should be used?<br>
<br>
6) A standard Configuration template?<br>
<br>
The Metacello tutorial is very useful as far as the configuration goes but it falls short of getting into the details of what it means to provide a 'working' configuration. Testing the configuration isn't covered (is there a way to get back to a 'clean' state?); bootstrapping isn't covered; the meaning of #isMetacelloConfig, #metacelloVesion:loads:, #lastMetacelloVersionLoad and several other -seemingly random- methods that can be found on most -but not all- of the configurations. There is no indication on what these do, if they're required, recommended, or optional. Is there some 'standard' Configuration template that people can use to avoid guessing about which parts of the boilerplate to copy from some other configuration?<br>
<br>
That's it for now. Thanks for any insights on any of these issues.<br>
<br>
Cheers,<br><font color="#888888">
- Andreas<br>
<br>
</font></blockquote></div><br>